This invention relates to electrochemical cells having solid electrolyte of tubular form separating a liquid alkali metal forming an anode from a liquid cathodic reactant. Such cells operate at an elevated temperature, typically above 200.degree. C. A sodium-sulphur cell, which normally operates between 300.degree. and 350.degree. C but which may operate between 270.degree. and 400.degree. C is a well known example of a cell having solid electrolyte.
The electrolyte material is a material through which ions of the alkali metal can migrate. A number of such solid electrolyte materials are known; in the case of sodium-sulphur cells; it is the usual practice to employ .beta.-alumina ceramic material. This material like other known solid electrolytes has only a limited mechanical strength and one of the principal courses of cell failure is the breakage of the electrolyte tube. Quite apart from the loss of the cell in a battery due to the breakage of a tube, there is also a possibility of risk of damage to surrounding equipment or personnel in the event of an electrolyte breakage if there is sudden mixing of a large quantity of liquid alkali metal with the cathodic reactant.